ITV %(series) output template no longer works

[torbs723]

Checklist

• I'm reporting a broken site support
• I've verified that I'm running youtube-dl version 2020.09.20
• I've checked that all provided URLs are alive and playable in a browser
• I've checked that all URLs and arguments with special characters are properly quoted or escaped
• I've searched the bugtracker for similar issues including closed ones

Verbose log

[debug] System config: []
[debug] User config: []
[debug] Custom config: []
[debug] Command-line args: ['https://www.itv.com/hub/john-bishops-great-whale-re
scue/2a6455a0001', '-o', 'f:/%(series)s/%(title)s.%(ext)s', '-v']
[debug] Encodings: locale cp1252, fs mbcs, out cp850, pref cp1252
[debug] youtube-dl version 2020.09.20
[debug] Python version 3.4.4 (CPython) - Windows-7-6.1.7601-SP1
[debug] exe versions: none
[debug] Proxy map: {}
[debug] Using fake IP 25.128.103.19 (GB) as X-Forwarded-For.
[ITV] 2a6455a0001: Downloading webpage
[ITV] 2a6455a0001: Downloading XML
WARNING: Unable to download XML: HTTP Error 504: Gateway Time-out
[ITV] 2a6455a0001: Downloading JSON metadata
[ITV] 2a6455a0001: Downloading m3u8 information
[debug] Default format spec: best/bestvideo+bestaudio
[debug] Invoking downloader on 'https://itvpnpdotcom.content.itv.com/2-6455-0001
-001/18/1/VAR012/2-6455-0001-001_18_1_VAR012.ism/2-6455-0001-001_18_1_VAR012-aud
io=128000-video=1535983.m3u8'
[hlsnative] Downloading m3u8 manifest
[hlsnative] Total fragments: 467
[download] Destination: f:\NA\John Bishop's Great Whale Rescue - Series 1 - Epis
ode 1.mp4
[download]   3.0% of ~565.03MiB at  8.65MiB/s ETA 03:03

Description

Up until a couple of days ago, using %(series) in the output template for ITV worked fine. Suddenly it has stopped picking up the series name and uses NA instead. In the example above, this template would have given me f:\John Bishop's Great Whale Rescue\John Bishop's Great Whale Rescue - Series 1 - Episode 1.mp4 before. But now gives me f:\NA\John Bishop's Great Whale Rescue - Series 1 - Episode 1.mp4